Pulsed-laser epitaxy of topological insulator Bi2Te3 thin films

Determining optimized conditions necessary to achieve high-quality films by pulsed laser deposition (PLD) for materials with multiple volatile elements is challenging. In this work, we present the optimized growth of epitaxial films of the topological insulator Bi2Te3 on Al2O3 (0001) substrates using PLD. It is found that the key to maximize film quality requires balanced control of the Ar background pressure (P-Ar) and growth temperature (T-G). Within a narrow window (200 <= P-Ar < 350 mTorr and 300 <= T-G < 350 degrees C), we find that Bi2Te3 thin films are flat, stoichiometric, and of the highest crystalline quality. This is a result of balancing the kinetics of ablated species in the PLD plume and the bulk thermodynamics of Bi2Te3. This work demonstrates that a careful optimization of the growth parameters can enable PLD to successfully grow multielemental materials containing volatile constituents. (C) 2019 Author(s).